Int.J.Curr.Microbiol.App.Sci (2014) 3(4): 501-506
ISSN: 2319-7706 Volume 3 Number 4 (2014) pp. 501-506
http://www.ijcmas.com
Original Research Article
A reviving preliminary evoke on few xylanase producing fungal isolates
from different ecological niche
Vishal Kumar, Pragya Pandey, Shivani Gupta, Pratyoosh Shukla*
1
Enzyme Technology and Protein Bioinformatics Laboratory, Department of
Microbiology, Maharshi Dayanand University, Rohtak-124001, Haryana, India
*Corresponding author
ABSTRACT
Keywords
Fungi;
YPSS media;
Xylanase,
Thermomyces
lanuginosus;
Aspergillus
sp.I.
In the present pre-screening report we describe the occurrence of few xylanase
producing fungi from different ecological niche i.e. soil samples and plants debris
samples. In the present work, diverse soil samples were collected from these sites
and fungal isolates were grown on YPSS media. Among five isolates three
different fungal isolates as identified morphologically through colonial morphology
and adapting basic microbiological procedures were TMDU1 (Thermomyces
lanuginosus), TMDU2 (Aspergillus sp.I) and TMDU3 (Aspergillus sp.II). The
qualitative xylanase assay was carried out which revealed that all the selected
isolates are xylanase producer. Further, TMDU1 (Thermomyces lanuginosus spp.)
was selected for further studies owing to its better xylanase producing capability.
Further, few studies on physiological profiles of these isolates suggested xylan and
yeast extract as best carbon and nitrogen source respectively..
Introduction
xylan, among them xylanase plays an
important role (Takahashi et al 2013).
Xylanase is an industrially important
enzyme which degrades xylan randomly
by its endo-1,4- -xylanase activity and
produces xylose, xylooligosaccharides and
xylobiose (Sharma and Kumar, 2013).
Xylanases have been found applications in
paper and pulp industries and in the
production of bio-ethanol etc (Bhat and
Hazlewood,
2001).
For
industrial
applications, xylanases must be optimally
active in alkaline range and high
temperatures (Shrivastava et al 2011).
Lignocellulose is the chief component of
the overall ecological biomass it is
composed
of
major
biological
macropolymers
such
as
cellulose,
hemicelluloses and lignin. Hemicelluloses
are complex mixtures of different
polymers such as xylan, mannan, galactan,
arabinan or other heteropolymers (Verma
and Satyanarayana, 2012). Xylan is a
major polysaccharide which is composed
of xylose units linked by -1,4 glycosidic
linkage, a mixture of hydrolytic enzymes
is required to complete degradation of
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Int.J.Curr.Microbiol.App.Sci (2014) 3(4): 501-506
There
are
several
groups
of
microorganisms that are very rich sources
of thermostable xylanases, such as
bacteria, actinomycetes, and fungi
(Suneetha, 2011; Kamble and Jadhav,
2012). Among these groups several genus
of filamentous fungi secrete high amounts
of extracellular thermophilic xylanases.
There is some important genus of
filamentous fungi, which produces
xylanases
such
as
Thermomyces,
Trichoderma, Aspergillus etc. (Takahashi
et al 2013; Shrivastava et al 2013).
Themomyces lanuginosus (previously
known as Humicola lanuginose) is a
thermophilic fungus widely distributed in
self-heating mass of organic debris and
soil (Singh et al 2003). This fungus
produces thermostable and alkalistable
xylanases which is best suitable for biobleaching process in paper and pulp
industry. In the present work, we are
reporting a swift description on few
xylanase producing fungal isolates from
different ecological niche.
maintained on YPSS slants and stored at
4°C. The slant cultures were sub cultured
every month.
Primary screening (Zone of clearance)
Fungal isolates were screened for xylanase
production on Czapek s agar medium
(Birch wood Xylan- 5 g/l, Peptone- 5 g/ l,
K2HPO4- 1 g/l, MgSO4 - 1 g/l, Agar 20
g/l). After inoculation the plates were kept
at 50°C for 6 days and then the plate was
treated with Congo red and washed with 1
M NaCl to observe the solubilisation zone
(Tallapragada and Venkatesh, 2011). The
confirmed fungal isolates were found to be
xylanase positive and some selected
isolates were maintained on YPSS agar
plates for further studies.
Qualitative Enzyme Assay
Spore Suspension
Slants were prepared in Erlenmeyer
conical flasks each of 250 ml containing
50 ml of YPSS agar medium. Each fungal
isolates were inoculated in respective flask
and incubated at 50°C for 7 days. A saline
solution in 150 ml distilled water by
adding 0.15 ml Tween-80 (0.01%) and
1.23 g NaCl was prepared. A quantity of
50 ml of this solution was added in each
flask and mycelium was scratched with a
sterilized loop and filtered with autoclaved
filter assembly.
Materials and Methods
Sample, media and growth conditions
The different soil samples and plants
debris samples were collected from the pot
and garden of M.D. University, Rohtak.
Soil suspensions in sterilized distilled
water (0.1 g/ml) were prepared and
serially diluted from 10-1 to 10-3 dilutions
and 100 µl of each diluted sample were
spread onto agar plates (YPSS: Yeast
extract- 4 g/l, Soluble Starch- 15 g/l ,
MgSO4- 1 g/ l, K2HPO4- 1 g/l, Agar- 20 g/
l ; PDA: Potato infusion- 200 g/l, Dextrose
20 g/ l, Agar 20 g/ l; SDA: Dextrose 40
g/l, Peptone 10 g/l , Agar 20 g/l )
containing 0.8 g/l Kanamycin. The plates
were incubated at 50oC for 3-4 days.
Fungal colonies were isolated and
Solid State Fermentation (SSF)
Solid State Fermentation for xylanase
production was carried out in Erlenmeyer
flasks (250 ml) containing 10 g of wheat
bran as substrate which was moisturised
with 10 ml of distilled water. These flasks
were sterilized and were inoculated with 1
ml of spore suspension at concentration
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Int.J.Curr.Microbiol.App.Sci (2014) 3(4): 501-506
105 -106/ml and the flasks were incubated
at 50°C in stationary condition. The
samples were obtained after 72 hrs and
were filtered using filter paper (Whatman
no. 1). Further, the clear supernatant was
collected for xylanase assay.
Morphological and microscopic
characters
The isolates TMDU1 showing gradual
colour change during its growth due to
pigment production. Initially at second day
it shows white filamentous growth, which
gradually turned light yellowish to light
brown it showed brown colour at fourth
day and finally, at sixth day it was wine
coloured on YPSS medium. During
microscopic examination of TMDU1 it
was observed small conidia were attached
to hyphae all over its length and free
conidia which get detached from hyphea
were randomly scattered as visible under
light microscope. Whereas TMDU2 and
TMDU3 were black and brownish yellow
in colour and there were no significant
colour change were observed. It was
studied under microscope TMDU2 have
large globose conidia and TMDU3 have
comparatively small columner conidia
attached to terminal end of hyphae.
Xylanase Assay
Xylanase activity was determined by
measuring the amount of reducing sugars
liberated from birchwood xylan used as a
substrate. Dinitrosalicylic acid (DNS)
method was used to determine reducing
sugar concentration (Shrivastava, et al.
2011). The substrate was prepared by
dissolving birchwood xylan in acetate
buffer pH 5.0 (1.0% w/v). The reaction
mixture containing 1 ml of substrate
solution and 1 ml of enzyme solution
(crude enzyme) and incubated for 30 min
at 50ºC, then the reaction was stopped by
adding 3 ml of DNS reagent and reading
were taken by spectrophotometer at 540
nm.
Xylanase estimation
Results and Discussion
All the three isolates were producing
colour during xylanase assay with DNS
the isolate TMDU1 was showing highest
colour intensity (OD 0.684) so this isolate
was recognised as best xylanase producer.
This
isolate
was
confirmed
as
Thermomyces sp. by morphological
characteristics and microscopic conidial
and hyphae structures characteristics.
Isolation and primary Screening
A total of five fungal strains namely
TMDU1, TMDU2, TMDU3, TMDU4 and
TMDU5 were isolated from the soil and
plant debris sample. All of these isolates
were showing optimum growth at 50°C.
All of these thermophilic fungal isolates
were screened for xylanase production on
Czapek Dox Agar medium. It was
observed that only three fungal isolates
TMDU1, TMDU2 and TMDU3 were able
to grow on this medium. The results of
primary screening (zone of clearance)
presented that TMDU1 showing maximum
xylanase production as compared to other
two isolates viz. TMDU2 and TMDU3.
A total of five thermophilic fungal isolates
were recorded from different ecological
niche such as potted plant, soil from
garden, plant debris from garden. Three
isolates (TMDU1, TMDU2 and TMDU3)
were found xylanase producers; this
reflects that a high percentage (60%) of
xylanase producers is prevalent in these
samples. Further these isolates were
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Int.J.Curr.Microbiol.App.Sci (2014) 3(4): 501-506
Figure I Thermomyces lanuginosus TMDU1 (96 Hrs old culture)
Figure II Thermomyces lanuginosus TMDU1 (40X) showing hyphae and condidia
Table.1 Morphological and microscopic characteristics of different fungal isolates
and xylanase producing capability
Isolate
No.
TMDU1
TMDU2
TMDU3
TMDU4
TMDU5
Colony characteristics
Regular change in colour
pale white to dark brown,
mycelial growth spreaded
on whole plate
Black
coloured,
not
significant change in
colour, mycelia
mat
with regular margin
Brownish
yellow
coloured, slight colour
change
yellow
to
brownish yellow, regular
shaped margin
White coloured mat have
oval shape with regular
margin
Green coloured powdery
growth with, no colour
change , irregular margin
Isolate
Identification
Xylanase producing
capability/Zone of
clearance
Small conidia were attached
to hyphae all over the its
length and some conidia get
deattached from hyphae
spreaded randomly
Large
globose
conidia
attached at the tip of hyphae
Thermomyces
sp.
+++
Aspergillus
sp.I
++
Small columner conidia
attached at the tip of hyphae
Aspergillus
sp.II
+
Not identified
Not identified
nd
Not identified
Not identified
nd
Microscopic identification
Abbreviations:+++: Excellent; ++: Good;
+: Fair nd: Not detected
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Int.J.Curr.Microbiol.App.Sci (2014) 3(4): 501-506
identified on the basis of their
morphological
and
microscopic
characteristics which revealed them as
Thermomyces sp. (TMDU1), Aspergillus
sp.I (TMDU2), Aspergillus sp II
(TMDU3). A review of literature suggests
that there are related studies were reported
by Takahashi et al (2013) and Shrivastava
et al. (2013). Although there are several
other reports on xylanase producing fungal
species such as Penicillium sp.,
Chaetomium sp., Fusarium sp. etc.
(Sharma and Kumar, 2013) but
Thermomyces sp. is reported as one of the
best xynalase producers by many
researchers, The reports of xylanase
production
from
Thermomyces
lanuginosus IOC-4145 (Monica et al
2003), Thermomyces lanuginosus DSM
5826 (Khucharoenphaisana et al 2008) and
Thermomyces
lanuginosus
SS8
(Shrivastava et al 2011) are noteworthy in
this perception. It is also envisaged that
Thermomyces lanuginosus xylanases are
found to be thermostable and pH tolerant
so they can be used as most excellent
appropriate choice for the pulp and paper
industry. The further purification and
bioprocess optimization for such xylanases
at lab scale and pilot scale are under
progress that may interpret fascinating
results.
application of xylanases as well as in
designing new enzymes for their use in
above-mentioned industries.
Acknowledgment
The authors duly acknowledge the
financial support from SERB, Department
of Science and Technology, Govt. of India
(DST Fast Track Grant. No. SR/FT/LS31/2012).
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